Ordinarily, internal hemorrhoids are anatomically located above the anal dentate line on the lateral side of the rectal wall (FIG. 4). Currently, banding is the most commonly used method to treat internal hemorrhoids in a clinical setting. Banding devices available on the market have a straight open head. While such banding devices have been used successfully in hemorrhoid bandings, they have some shortcomings for blind insertion and banding. For example, the operator must be able to grasp the target tissue accurately. Because the banding head may not make good contact with the hemorrhoid tissue, the dentate line of the anus might move upward during the procedure, and the rectal wall muscle layer might be banded instead. This can lead to excessive tissue damage, as well as post-banding complications, especially pain and infection. Further, the operator may need to use an anal scope to locate the hemorrhoid and then insert the head of a straight-head banding device into the rectum to do the banding. However, due to the anatomy of hemorrhoids and the rectum (FIG. 4), the operator often can have difficulty sucking the hemorrhoid tissues into the device (FIG. 5). The main reason is that the hemorrhoid-containing mucosal layer wall of the rectum is parallel to the wall of the banding device, and the opening of the banding device will be almost perpendicular to the tissues to be banded. To maneuver the device head into close contact with the hemorrhoid tissue, the operator may need to repeatedly adjust the device angle or even reinsert it. This can cause pain and discomfort to patients and also can lengthen the procedure time. Besides, the operator can only have very limited room to adjust the angle of the device due to the anatomy of the rectum.
More recently, efforts have been made to overcome the above disadvantages associated with straight-head banding devices. However, shortcomings still exist. For example, with a straight-head device that uses the pressure from a tightly sealed fluid compartment to release the banding rubber or a kinked-head device that uses sealed fluid to push the inner cylinder and then a spring connected to the cylinder to push the outer cylinder to release the banding rubber, these banding devices can be quite complicated and unreliable. In another device, an elastic-type banding tube may be used; however, because the colon wall contracts, it is difficult to bend the tip of the device after it has been inserted into the rectum. Hence this type of device does little to solve the problem that the opening of a banding device may not grasp the targeted hemorrhoid tissue accurately.